REMANSO TALISMA, Brazil — The death of a myth begins with stinging eyes and heaving chests here on the edge of the Amazon rain forest.
Every year, fire envelops the jungle, throwing up inky billows of smoke that blot out the sun. Animals flee. Residents for miles around cry and wheeze, while the weak and unlucky develop serious respiratory problems.
When the burning season strikes, life and health in the Amazon falter, and color drains out of the riotous green landscape as great swaths of majestic trees, creeping vines, delicate bromeliads and hardy ferns are reduced to blackened stubble.
But more than just the land, these annual blazes also lay waste to a cherished notion that has roosted in the popular mind for decades: the idea of the rain forest as the "lungs of the world."
Ever since saving the Amazon became a fashionable cause in the 1980s, championed by Madonna, Sting and other celebrities, the jungle has consistently been likened to an enormous recycling plant that slurps up carbon dioxide and pumps out oxygen for us all to breathe, from Los Angeles to London to Lusaka.
Think again, scientists say.
Far from cleaning up the atmosphere, the Amazon is now a major source for pollution. Rampant burning and deforestation, mostly at the hands of illegal loggers and of ranchers, release hundreds of millions of tons of carbon dioxide into the skies each year.
Brazil now ranks as one of the world's leading producers of greenhouse gases, thanks in large part to the Amazon, the source for up to two-thirds of the country's emissions.
"It's not the lungs of the world," said Daniel Nepstad, an American ecologist who has studied the Amazon for 20 years. "It's probably burning up more oxygen now than it's producing."
Scientists such as Nepstad prefer to think of the world's largest tropical rain forest as Earth's air conditioner. The region's humidity, they say, is vital in climate regulation and cooling patterns in South America -- and perhaps as far away as Europe.
The Amazon's role as a source of pollution, not a remover of it, is directly linked to the galloping rate of destruction in the region over the last quarter-century.
The dense and steamy habitat straddles eight countries and is home to up to 20% of the world's fresh water and 30% of its plant and animal species.
